创建Kotlin项目

创建 kotlin maven 项目

通过 start.srping.io 项目创建基于maven构建系统的kotlin项目

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curl -o starter.zip  "https://start.spring.io/starter.zip?type=maven-project\
&language=kotlin\
&bootVersion=2.5.3\
&baseDir=demo\
&groupId=com.example\
&artifactId=demo\
&name=demo\
&description=Demo%20project%20for%20Spring%20Boot\
&packageName=com.example.demo\
&packaging=jar\
&javaVersion=11"

由生成的maven构建文件pom.xml中的配置可知:

在dependency章节加了kotlin-reflect(反射)与kotlin-stdlib包

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...
<dependency>
    <groupId>org.jetbrains.kotlin</groupId>
    <artifactId>kotlin-reflect</artifactId>
</dependency>
<dependency>
    <groupId>org.jetbrains.kotlin</groupId>
    <artifactId>kotlin-stdlib-jdk8</artifactId>
</dependency>
...

在plugin章节中添加kotlin-maven-plugin插件

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<plugin>
    <groupId>org.jetbrains.kotlin</groupId>
    <artifactId>kotlin-maven-plugin</artifactId>
    <configuration>
        <args>
            <arg>-Xjsr305=strict</arg>
        </args>
        <compilerPlugins>
            <plugin>spring</plugin>
        </compilerPlugins>
    </configuration>
    <dependencies>
        <dependency>
            <groupId>org.jetbrains.kotlin</groupId>
            <artifactId>kotlin-maven-allopen</artifactId>
            <version>${kotlin.version}</version>
        </dependency>
    </dependencies>
</plugin>

创建 kotlin gradle 项目

通过 start.srping.io 项目创建基于 gradle 构建系统的kotlin项目

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curl -o starter.zip  "https://start.spring.io/starter.zip?type=gradle-project\
&language=kotlin\
&bootVersion=2.5.3\
&baseDir=demo\
&groupId=com.example\
&artifactId=demo\
&name=demo\
&description=Demo%20project%20for%20Spring%20Boot\
&packageName=com.example.demo\
&packaging=jar\
&javaVersion=11"

gradle构建工具的构建脚本build.gradle现已支持kotlin脚本，
如果项目语言选择了kotlin语言,默认使用kotlin编写build.gradle,并以kts结尾,如:build.gradle.kts.
如果项目语言选择了java语言,使用groovy编写build.gradle,如:build.gradle.

对比 settings.gradle 与 build.gradle的差异

由此可见kotlin与groovy语法略有不同

settings.gradle.kts

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rootProject.name = "demo"

settings.gradle

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rootProject.name = 'demo'

build.gradle.kts

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import org.jetbrains.kotlin.gradle.tasks.KotlinCompile

plugins {
	id("org.springframework.boot") version "2.5.3"
	id("io.spring.dependency-management") version "1.0.11.RELEASE"
	kotlin("jvm") version "1.5.21"
	kotlin("plugin.spring") version "1.5.21"
}

group = "com.example"
version = "0.0.1-SNAPSHOT"
java.sourceCompatibility = JavaVersion.VERSION_11

repositories {
	mavenCentral()
}

dependencies {
	implementation("org.springframework.boot:spring-boot-starter")
	implementation("org.jetbrains.kotlin:kotlin-reflect")
	implementation("org.jetbrains.kotlin:kotlin-stdlib-jdk8")
	testImplementation("org.springframework.boot:spring-boot-starter-test")
}

tasks.withType<KotlinCompile> {
	kotlinOptions {
		freeCompilerArgs = listOf("-Xjsr305=strict")
		jvmTarget = "11"
	}
}

tasks.withType<Test> {
	useJUnitPlatform()
}

build.gradle

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plugins {
	id 'org.springframework.boot' version '2.5.3'
	id 'io.spring.dependency-management' version '1.0.11.RELEASE'
	id 'java'
}

group = 'com.example'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = '11'

repositories {
	mavenCentral()
}

dependencies {
	implementation 'org.springframework.boot:spring-boot-starter'
	testImplementation 'org.springframework.boot:spring-boot-starter-test'
}

test {
	useJUnitPlatform()
}